1. Field of the Invention
This invention relates in general to a pulse amplitude modulation generator, and, more specifically, to an Emitter Coupled Logic (ECL) pulse amplitude modulator that generates multilevel signals at high frequencies.
2. Description of Related Art
Pulse Amplitude Modulation (PAM) signals are used to transmit information and control logic systems throughout the world. However, PAM signals at high frequencies are difficult to generate because the speed and bandwidth required to generate multi-level pulses are typically difficult to produce with present electronics systems.
The problem of generating PAM signals is compounded when Emitter Coupled Logic (ECL) outputs are desired. Further, the use of ECL that has accurate complimentary time and amplitude characteristics makes the generation of PAM ECL signals even more difficult.
It can be seen, then, that there is a need for PAM signals at high frequencies. It can also be seen that there is a need for PAM signals that are compatible with ECL. It can also be seen then that there is a need for PAM signals that are compatible with ECL that have accurate complimentary time and amplitude characteristics.